Conventionally, electronic equipments, such as personal computers, portable or mobile telephones, PDAs (personal digital assistants), digital cameras, video cameras, music players, game machines, and car navigation systems, are equipped with a card connector adapted for use with a various kinds of memory cards such as an a mini SD® card, a TransFlash® card, a micro SD® card, and the like.
Recently, a rapid miniaturization of electronic equipments creates a tendency of a rapid miniaturization of memory cards and card connectors. The card connector tends to be disposed at a less visible location, such as the side and bottom surfaces of electronic equipment, with the exclusion of locations where members such as a display screen, operation buttons and the like are disposed. Consequently, a card can be inserted upside down, namely improperly. If a card is inserted improperly, the outside area of the card other than its pad may abut against a connecting terminal of a card connector. As a result, the connecting terminal might be incidentally bent or damaged. To this end, there has been proposed a card connector that prevents an improper insertion of a card (for example, refer to Japanese Patent Application Laid-Open (kokai) No. 2004-335172).
FIG. 12 is a perspective view showing a conventional card connector. In FIG. 12, the reference numeral 301 designates a chassis to form a housing of a card connector. The chassis 301 has a base 302 that is a molded component formed of synthetic resin, and a cover 303 formed of a metallic plate and secured to the base 302. An insertion space (not shown), into which a card is inserted, is provided in the chassis 301, and a card insertion opening 304 is formed at the rear end of the casing 301. Guide grooves 305 for guiding a card are formed on both sidewalls of the base 302, respectively. The card inserted from the card insertion opening 304 can be shifted along the guide grooves 305 in the direction indicated by an arrow. A plurality of terminals 308 formed of metal are disposed in the vicinity of the front end of the base 302, so that they come in contact with a face electrode of the card inserted in the inside of the chassis 301 to establish electrical conduction thereto.
The cover 303 is further provided with a faceplate part 306 for covering an open upper surface of the base 302. The faceplate part 306 is provided with an engaging projection 307 for preventing an improper insertion. If a card is inserted upside down, namely improperly, abutment of the engaging projection 307 against the front upper edge of the improperly inserted card holds the card against further travel. This prevents the terminals 308 from being damaged by the improperly inserted card. Meanwhile, if the card is inserted in its proper attitude, the engaging projection 307 is received in a recess part formed near the front end of the upper surface of the card. Therefore, the properly inserted card travels to the front end within the inside of the chassis 301, so that its face electrode comes into mechanical and electrical contact with the terminals 308 and establishes electrical conduction thereto.
Nevertheless, because the above-mentioned conventional card connector has the engaging projection 307 formed in the cover 303, it is required that the recess part for receiving the engaging projection 307 is formed near the front end of the upper surface of the card. It is, however, difficult to form the recess in a card that is small in size and thickness thus making it extremely difficult to use with a small card. Further, the engaging projection 307 is both the primary measure for retaining a correctly inserted card and the measure for preventing incorrect insertion. As a result, a part thereof is subjected to a force exerted by the card upon abutment, so that the engaging projection 307 and the circumference of the engaging projection 307 in the cover 303 might be deformed. Also in the improperly inserted card, a part thereof is subjected to the reaction force from the engaging projection 307, so that portions defining the external wall of the card might be damaged.